﻿<!DOCTYPE html>
<html>
<head>
  <meta charset="UTF-8">
  <title>HTML Context Menu</title>
  <meta name="description" content="Context menus implemented in HTML rather than as GoJS objects." />
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <!-- Copyright 1998-2019 by Northwoods Software Corporation. -->

  <style type="text/css">
    /* CSS for the traditional context menu */
    #contextMenu {
      z-index: 10002;
      position: absolute;
      left: 5px;
      border: 1px solid #444;
      background-color: #F5F5F5;
      display: none;
      box-shadow: 0 0 10px rgba( 0, 0, 0, .4 );
      font-size: 12px;
      font-family: sans-serif;
      font-weight: bold;
    }

      #contextMenu ul {
        list-style: none;
        top: 0;
        left: 0;
        margin: 0;
        padding: 0;
      }

      #contextMenu li a {
        position: relative;
        min-width: 60px;
        color: #444;
        display: inline-block;
        padding: 6px;
        text-decoration: none;
        cursor: pointer;
      }

      #contextMenu li:hover {
        background: #CEDFF2;
        color: #EEE;
      }

      #contextMenu li ul li {
        display: none;
      }

        #contextMenu li ul li a {
          position: relative;
          min-width: 60px;
          padding: 6px;
          text-decoration: none;
          cursor: pointer;
        }

      #contextMenu li:hover ul li {
        display: block;
        margin-left: 0px;
        margin-top: 0px;
      }
  </style>

  <script src="../release/go.js"></script>
  <script src="../assets/js/goSamples.js"></script>  <!-- this is only for the GoJS Samples framework -->
  <script id="code">

    var myDiagram = null;

    function init() {
      if (window.goSamples) goSamples();  // init for these samples -- you don't need to call this
      var $ = go.GraphObject.make;  // for conciseness in defining templates

      myDiagram =
        $(go.Diagram, "myDiagramDiv",  // create a Diagram for the DIV HTML element
          { "undoManager.isEnabled": true });

      // This is the actual HTML context menu:
      var cxElement = document.getElementById("contextMenu");

      // Since we have only one main element, we don't have to declare a hide method,
      // we can set mainElement and GoJS will hide it automatically
      var myContextMenu = $(go.HTMLInfo, {
        show: showContextMenu,
        mainElement: cxElement
      });

      // define a simple Node template (but use the default Link template)
      myDiagram.nodeTemplate =
        $(go.Node, "Auto",
          { contextMenu: myContextMenu },
          $(go.Shape, "RoundedRectangle",
            // Shape.fill is bound to Node.data.color
            new go.Binding("fill", "color")),
          $(go.TextBlock,
            { margin: 3 },  // some room around the text
            // TextBlock.text is bound to Node.data.key
            new go.Binding("text", "key"))
        );

      // create the model data that will be represented by Nodes and Links
      myDiagram.model = new go.GraphLinksModel(
        [
          { key: "Alpha", color: "crimson" },
          { key: "Beta", color: "chartreuse" },
          { key: "Gamma", color: "aquamarine" },
          { key: "Delta", color: "gold" }
        ],
        [
          { from: "Alpha", to: "Beta" },
          { from: "Alpha", to: "Gamma" },
          { from: "Beta", to: "Beta" },
          { from: "Gamma", to: "Delta" },
          { from: "Delta", to: "Alpha" }
        ]);

      myDiagram.contextMenu = myContextMenu;

      // We don't want the div acting as a context menu to have a (browser) context menu!
      cxElement.addEventListener("contextmenu", function(e) {
        e.preventDefault();
        return false;
      }, false);

      function showContextMenu(obj, diagram, tool) {
        // Show only the relevant buttons given the current state.
        var cmd = diagram.commandHandler;
        document.getElementById("cut").style.display = cmd.canCutSelection() ? "block" : "none";
        document.getElementById("copy").style.display = cmd.canCopySelection() ? "block" : "none";
        document.getElementById("paste").style.display = cmd.canPasteSelection() ? "block" : "none";
        document.getElementById("delete").style.display = cmd.canDeleteSelection() ? "block" : "none";
        document.getElementById("color").style.display = (obj !== null ? "block" : "none");

        // Now show the whole context menu element
        cxElement.style.display = "block";
        // we don't bother overriding positionContextMenu, we just do it here:
        var mousePt = diagram.lastInput.viewPoint;
        cxElement.style.left = mousePt.x + "px";
        cxElement.style.top = mousePt.y + "px";
      }

    }

    // This is the general menu command handler, parameterized by the name of the command.
    function cxcommand(event, val) {
      if (val === undefined) val = event.currentTarget.id;
      var diagram = myDiagram;
      switch (val) {
        case "cut": diagram.commandHandler.cutSelection(); break;
        case "copy": diagram.commandHandler.copySelection(); break;
        case "paste": diagram.commandHandler.pasteSelection(diagram.lastInput.documentPoint); break;
        case "delete": diagram.commandHandler.deleteSelection(); break;
        case "color": {
          var color = window.getComputedStyle(document.elementFromPoint(event.clientX, event.clientY).parentElement)['background-color'];
          changeColor(diagram, color); break;
        }
      }
      diagram.currentTool.stopTool();
    }

    // A custom command, for changing the color of the selected node(s).
    function changeColor(diagram, color) {
      // Always make changes in a transaction, except when initializing the diagram.
      diagram.startTransaction("change color");
      diagram.selection.each(function(node) {
        if (node instanceof go.Node) {  // ignore any selected Links and simple Parts
          // Examine and modify the data, not the Node directly.
          var data = node.data;
          // Call setDataProperty to support undo/redo as well as
          // automatically evaluating any relevant bindings.
          diagram.model.setDataProperty(data, "color", color);
        }
      });
      diagram.commitTransaction("change color");
    }
  </script>
</head>
<body onload="init()">
<div id="sample">
  <div style="display: inline-block;">
    <!-- We make a div to contain both the Diagram div and the context menu (such that they are siblings)
         so that absolute positioning works easily.
         This DIV containing both MUST have a non-static CSS position (we use position: relative)
         so that our context menu's absolute coordinates work correctly. -->
    <div style="position: relative;"  >
      <div id="myDiagramDiv" style="border: solid 1px black; width:400px; height:400px"></div>
      <div id="contextMenu">
        <ul>
          <li id="cut" onclick="cxcommand(event)"><a href="#" target="_self">Cut</a></li>
          <li id="copy" onclick="cxcommand(event)"><a href="#" target="_self">Copy</a></li>
          <li id="paste" onclick="cxcommand(event)"><a href="#" target="_self">Paste</a></li>
          <li id="delete" onclick="cxcommand(event)"><a href="#" target="_self">Delete</a></li>
          <li id="color" class="hasSubMenu"><a href="#" target="_self">Color</a>
            <ul class="subMenu" id="colorSubMenu">
                <li style="background: crimson;" onclick="cxcommand(event, 'color')"><a href="#" target="_self">Red</a></li>
                <li style="background: chartreuse;" onclick="cxcommand(event, 'color')"><a href="#" target="_self">Green</a></li>
                <li style="background: aquamarine;" onclick="cxcommand(event, 'color')"><a href="#" target="_self">Blue</a></li>
                <li style="background: gold;" onclick="cxcommand(event, 'color')"><a href="#" target="_self">Yellow</a></li>
            </ul>
          </li>
        </ul>
      </div>
    </div>

    <div id="description">
      <p>This demonstrates the implementation of a custom HTML context menu.</p>
      <p>For a light-box style HTML context menu implementation, see the <a href="htmlLightBoxContextMenu.html">LightBox Context Menu</a> sample.</p>
      <p>Right-click or tap-hold on a Node to bring up a context menu.
      If you have a selection copied in the clipboard, you can bring up a context menu anywhere to paste.</p>
    </div>
  </div>
</div>
</body>
</html>